Alpha-mangostin Suppresses Receptor Activator Nuclear Factor-κB Ligand-induced Osteoclast Formation and Bone Resorption in RAW264.7 Cells by Inhibiting the Extracellular Signal-Regulated Kinase and c-Jun N-Terminal Kinase Signaling

Background: Excessive osteoclast formation and over-activated function lead to a series of osteoclast-related diseases. Suppression of osteoclastogenesis is likely to be an effective means for the treatment of these diseases. Objective: In this study, we investigated the effects of alpha-mangostin (alpha-MAG), a natural compound derived from Garcinia mangostana, on osteoclast formation and function in RAW264.7 cells. Materials and Methods: Different concentrations of alpha-MAG were used to explore its effects on receptor activator of nuclear factor-kappa B ligand (RANKL)-induced osteoclastogenesis and further, we investigated the mechanism by Western Blotting. Results: The study revealed that alpha-MAG attenuated RANKL-induced osteoclastogenesis. Moreover, the effects were confirmed to be caused by the suppression of the phosphorylation of the extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) signaling and this inhibitory effect could be rescued by the administration of the JNK and p38 agonist anisomycin. Conclusion: The study results demonstrated that alpha-MAG could impair RANKL-induced osteoclastogenesis by inhibiting the ERK and JNK signaling pathways in RAW264.7 cells.